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(No Model.)

V T. A. EDISON. TELEPHONE. I V

170,274,577. Patented Mar. 27,1883.

' NITED TATES Aren't error,

THOMAS A. EDISON, OF MENLO PARK, NEW JERSEY.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No. 274,577, dated March2'7, 1883.

Application filed October 6, 1882. (No model.)

To all whom it may concern:

Be it known that I, THOMAS ALVA EDIsoN, of Menlo Park, in the State ofNew Jersey, have invented an Improvement in Telephones, (Case No. 159 ofwhich the following is a specification.

- This application is a division of my application filed November 18,1878, No. 159, and said division is made for the purpose of separatingfrom the said original application the different features of inventioninto three additional applications. The present I term Case No. 1590 77In my application No. 130, heretofore filed, the circuit passes throughplumbago or similar material, and the diaphragm that is acted upon bythe sound-waves serves to vary the eiectric tension by the extent ofsurface contact.

In my (Jase No. 151, patented April 30, 1878, No. 203,016, I have shownan induction-coil with primary and secondary circuits and receiving andtransmitting telephones. A carbon button in a circuit and acted upon bythe diaphragm is shown in my said Gase'15l and also in Case '141. Theseare not therefore claimed herein.

In my present improvement I make use of a surface or surfaces havingnumerous points produced by scores or due lines across the surface,preferably about at right angles to each other, and this surface orsurfaces are in the electric circuit and combined with the diaphragnnsothat the movement given to the diaphragm by the sound-waves will producegreater or less intimacy of contact at the scored surface and aconsequent rise and fall of electric tension. I also combine with abutton oi carbon or equivalent material in one circuit an electro-magnetin another circuit, the armature of which varies the pressure upon suchcarbon or other finely-divided material, and by this means repeats thetelephonic pulsations. I also construct the telephonic receiver resentsthe transmitting, receiving, and repeating instruments, the instrumentsat X being at one station and the instruments at G being at therepeating-station. Fig. 2 is a detached View of a modification of therepeatiuginstrument, and Fig. 3 is a face view of the tension-regulatorformed by a surface scored with numerous lines.

The telephonic transmitter A is made with a case containing thediaphragm or plate 0, against which the sound acts to vibrate the same.

, The plate 6 is in the bottom of a vulcanite cup or holder, 20, and canbe adjusted nearer to or farther from the diaphragm c by the screw 21. v

The tension-regulating device 9 is between the plate 0 and the secondplate, a, the wires 10 and 12 of the circuit to the battery Bconnecting, so thatthe circuit passes through these plates and theintervening tension-regulator.

- The tension-regulating device is composed of two contiguous surfaces,one or both of which are scored with numerous fine lines, so as toproduce a great number of contact-points. By adjusting the screw 21 theinitial pressure can be regulated, and the vibrations of the diaphragmdue to the action of sounds will vary the pressure and the extent ofsurface contact, so as to produce rise and fall of tension in thecircuit by bringing more or less of the points on the surface orsurfaces into contact.

In Fig. '3 I have shown the surface scored as aforesaid, and it is to beunderstood that the scoring is to be of the requisite fineness,preferably several thousand to the inch.

In the instrument A, Fig. l, the tensionregulator is composed of a stripof platina scored by lines of ruling at right angles, and folded, with apiece of felt, rubber, or similar material within the fold,and thescored surfaces in contact with the plates at and 6, respectivel y.Several layers of foil ruled as aforesaid maybe placed together, ifdesired, to obtain great resistance and variation in the electrictension of the circuit. The foil ruled as aforesaid is believed tooperate in the circuit in a similar manner to a carbon button.

Between the diaphragm c and plate a there is a short section of a tube,6, tolform a central I line, I, currents corresponding or [)lOPOliilOlFhearing.

The inductorium I has its primary included in the circuit to the batteryB and tensionregulator and its secondary to the line and ground. Thereceiving-telephone R is placed in the line-circuit passing through thesecondary of the inductorium. At the receiving-instrument It there is apermanent magnet, H, -and upon one pole there is a bar,23,forming at itsends the cores for the helices?) and 4, that are in the line-circuit,and upon the other pole of the magnet II, there is a bar, 24;, that isconnected at its ends to the diaphragms (Z d.

7 These diaphragms hence are polarized by induction, and are of onepolarity-say southwhile the cores of 3 and 4 are polarized north byinduction. Flexible tubes m, with earpieces, are connected to thechambers or cases holding the diaphragms d d, so that the sound isconveyed to the cars. This apparatus is not liable to becomedcmagnetized, because any current which passes through the helices I 3and 4 acts to increase the induced magnetism at one end of the bar 23 inproportion as it tends to decrease the induced magnetism in the'otherend. Thus there will be no tendency to injure the permanent magnet H;but the telephonic current will cause the diaphragms to respond by thechange of magnetism in the cores adjacent to the diaphragms.

The repeating-instrument at the station G contains an electro-magnet, Dthe helix of which isin the main-line circuit. Its core is adjacent toan iron plate or armature, and the variation of the magnetism resultingfrom the action of the current in the main lineincreases and decreasesthe pressure upon a button of carbon, g, or similar material, formingthetension-regulator in a second electric circuit. I have shown thelocal circuit from the battery B as passing to the plate fat one side ofthe circuit-regulator g, and to the adjusting device of the plate h atthe other side of the carbon or similar material, and in this localcircuit is the primary of the inductorium 1 the secondary of which is inthe line P to the distant receiving-instrument. core of theelectro-magnet13 to one pole of the permanent magnet A, so that it maybe polar ized by induction, and hence the line-current will increase ordecrease the magnetism of the core of B The armature-plate of the magnetB is shown upon'a lever, 0, having a fulcrum at 0, and the spring at (P,which should be adj ustable, serves to apply an initial pressure to thetension-regulator g, and I prefer to use a short cylinder, 6, betweenthe armaturefplate and the disk 1'', to insure a central bearing on thetension-regulator. When an .electricwave from the distant stationvariesthe power of the magnet B the pressure upon the tensionregulator gis decreased or increased, and the primary current from B acts in theinductori-um to translate or reproduce on the second I prefer to connectthe ate tothose sent from the instrument A.

The instrument shown in Fig. 2 is a very delicate translator, actingsimilarly tothat in Fig. 1. The electro-magnet B has a helix-in theline-circuit, as before, and A is its polar ized core. 0 is a diaphragm,and S is a'lever, the short end, it, of which is attracted by anadjustable magnet, H. Between the lever S and diaphragm 0 there are thepieces 14 and 15, of carbon or other finely-divided material, that actas a tension-regulator for the translatin g or repeating circuit thatpasses through the lever S and diaphragm O hence the rise and fall ofelectric tension in the repeatingcircuit will result from the vibrationsof the diaphragm, producing more or less pressure and intimacy ofcontact in the tension-regulator at 14 15, the initial pressure beingdetermined by the proximity of the magnet H to the lever S.

It will be observed that the vibrations of thediaphragm act upon thecarbons 14 and 15 to vary the electric tension in the circuit passingthrough them, and that the magnet H and lever Storm the resistancebehind the carbons.

It will be observed that in my telephone instruments I provide anelectric tension-regulatorhaving an extended surface, incontradistinction to a point or small bearing such as shown in myapplication No. 141, and instead of the electric-tension regulatorcoming directly into contact with the diaphragm, as in my application No. 130, I combine with the electric tens'ion-regulatin g device anintermediate bearing having'a small contact with the diaphragm and therequired extent of surface against the tension-regulator. This bear ingis non-elastic to transfer more positively to the tension-regulator thetremulo'us movements of the diaphragm, as distinguished from theyielding material-such as cork orrubber-- o as shown in my Patent No.203,016. If thecurrent passes through this non-elastic bearing piece, asat A, the same is to be of metal or other goodconductor.

Certain of the devices shown herein are not claimed, as they form thesubject of other applications.

I claim as" my inventionr 1. In a telephone, the combination, with thediaphragm and the tension-regulating device,

| i I i initial pressure to the tension-regulatonsubother circuit aetedupon by such diaphragm, connected with the diaphragm and the other and ayielding-pressure device to apply an with the said arm, substantially asset; forth.

Signedhy me this 30th day of March, A. D. m

stantially as set forth. 1882.

4. The combination; in a telephone, of a Witnesses: THOMAS A. EDISON.

diaphragm, e lever-arm, and two electrodes of GEO. T. PINCKNEY, carbonor similar material, one of which is HAROLD SERRELL.

